In pursuit of β-amino α-nitro β-trifluoromethyl ketones: nitro-Mannich vs Mannich-type reactions

The reactivity of alfa-nitro ketones with trifluoromethyl aldimines is studied for the first time. While under nitro-Mannich conditions only the facial stereoselectivity can be controlled, organocatalysed Mannich-type reactions allowed a complete control of absolute and relative stereoselectivity, leading to highly functionalised β-amino alfa-nitro β-trifluoromethyl compounds as diastereomerically pure compounds. A key role on the geometrical and/or facial stereoselectivity is played by the structure of reactants

Analysis of Passive Charge Balancing for Safe Current-Mode Neural Stimulation

Charge balancing has been often considered as one of the most critical requirement for neural stimulation circuits. Over the years several solutions have been proposed to precisely balance the charge transferred to the tissue during anodic and cathodic phases. Elaborate dynamic current sources/sinks with improved matching, and feedback loops have been proposed with a penalty on circuit complexity, area or power consumption. Here we review the dominant assumptions in safe stimulation protocols, and derive mathematical models to determine the effectiveness of passive charge balancing in a typical application scenario

A new one-pot synthesis of quinoline-2-carboxylates under heterogeneous conditions

Quinoline-2-carboxylates are an important subclass of quinoline derivatives largely present in a variety of biologically active molecules, as well as useful ligands in metal-catalyzed reactions. Herein, we present a new one-pot protocol for synthesizing this class of derivatives starting from beta-nitroacrylates and 2-aminobenzaldehydes. In order to optimize the protocol, we investigated several reaction conditions, obtaining the best results using the 2-tert-butylimino-2-diethylamino- 1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP) as solid base, in acetonitrile. Finally, we demonstrated the generality of our approach over several substrates which led to synthesize a plethora of functionalized quinolines-2-carboxylate derivatives in good overall yields

A new two-step synthesis of 2-alkylated 1, 4-diketones and α-alkylated γ-keto esters

2-Alkylated 1,4-diketones and a-alkylated g-keto esters can be easily prepared by a two-step procedure which involves first the conjugate addition of a nitroalkane to an enedione derivative in acetonitrile with DBU as base, followed by chemoselective hydrogenation of the C–C double bond (H2, 10% Pd/C) of the Michael adduct, obtained after elimination of nitrous acid.peer-reviewe

Intéraction entre le métabolisme azoté et la résistance du riz à la pyriculariose

L'intensification des pratiques agricoles, et notamment la fertilisation minérale azotée, influent sur l'expression de la résistance des plantes. Une mauvaise gestion de la fertilisation azotée peut entraîner dans certaines situations des pertes élevées en favorisant le développement d'agents pathogènes. Bien que ce phénomène ait été couramment observé au champ, peu de preuves ont été établies au niveau moléculaire d'une interaction entre les voix de défense et un des mécanismes majeur dans la productivité des céréales, le métabolisme azoté. La pyriculariose est une maladie du riz provoquée pas l'ascomycète Magnaporthe oryzae. Cette interaction modèle peut nous permettre de comprendre quels sont les mécanismes responsables de l'affaiblissement de la résistance du riz dans un système de culture intensif avec un haut niveau d'apport azoté. Pour répondre `a cette question, deux approches complémentaires sont utilisées : L'étude du contrôle génétique de la sensibilisation du riz par l'azote avec comme objectif la cartographie de QTL impliqués dans ce mécanisme. Le suivi de l'expression de gènes candidats impliqués dans les mécanismes de défense et du métabolisme azoté au cours des phases précoces de l'interaction. Les premiers résultats de cartographie génétique ont permis de mettre en évidence un QTL sur le chromosome 1 qui provoque une sensibilité accrue des variétés de riz en présence d'azote. Ce QTL contient plusieurs gènes candidats intéressants ayant un rôle dans la défense chez le riz : un cluster de NBS-LRR, un cluster de LRR-kinases de type Xa21 et un régulateur des défenses homologue `a PMR4. Le QTL contient également plusieurs gènes importants pour le métabolisme azoté comme le gène OsFBT1 codant pour une F-box induite lors de stress azoté et le gène codant pour la NADH glutamate synthase OsGLT1. Ce gène est un composant important pour la remobilisation de l'azote et le remplissage des grains et est considéré comme un candidat intéressant pour l'amélioration de la NUE (Nitrogen Use Efficiency) chez les céréales. Une cartographie plus fine est en cours pour réduire le nombre de gènes candidats pour ce QTL et permettre de poser de nouvelles hypothèses. L'approche moléculaire a quant à elle permis de mettre en évidence une répression partielle du système de défense du riz dans les jours suivant un apport excessif en azote. En particulier, les gènes de défense PR comme PBZ1 classiquement utilisés pour suivre le niveau d'expression de l'arsenal suggèrent qu'une répression transcriptionnelle d'une partie de l'arsenal aurait lieu. Cette répression des systèmes de défense pourrait expliquer une partie de l'augmentation de la sensibilité après un apport azoté. 64 (Résumé d'auteur

A neural probe with up to 966 electrodes and up to 384 configurable channels in 0.13 μm SOI CMOS

In vivo recording of neural action-potential and local-field-potential signals requires the use of high-resolution penetrating probes. Several international initiatives to better understand the brain are driving technology efforts towards maximizing the number of recording sites while minimizing the neural probe dimensions. We designed and fabricated (0.13-μm SOI Al CMOS) a 384-channel configurable neural probe for large-scale in vivo recording of neural signals. Up to 966 selectable active electrodes were integrated along an implantable shank (70 μm wide, 10 mm long, 20 μm thick), achieving a crosstalk of −64.4 dB. The probe base (5 × 9 mm2) implements dual-band recording and a 1

Impacto dos rendimentos de aposentadoria e pensão na redução da pobreza rural

Este trabalho analisa o impacto dos rendimentos de aposentadoria e pensão sobre a redução da pobreza no Brasil. Mais especificamente, a análise terá como foco as diferenças existentes entre as famílias das áreas urbanas e rurais do país, nos anos de 1995 e 2006. A hipótese central é de que as aposentadorias e pensões cumprem importante papel no rendimento das famílias mais pobres e das áreas rurais, contribuindo principalmente para a redução da pobreza nas regiões mais precárias do país. Esta dependência teria ainda aumentado no período analisado devido, sobretudo, à vinculação dos rendimentos de aposentaria e pensão ao salário mínimo e aos ganhos reais observados por este no período.------------------------This papers analyzes the impacts of retirement pensions on poverty reduction in Brazil. More specifically, the analyzes will focus the differences among families from urban and rural areas in this country, between 1995 and 2006. The central hypothesis is that the retirement pensions play an important role on the income of poorest families and those from rural areas, contributing mainly to poverty reduction in the most precarious Brazilian regions. This relationship had grown in this period due to the link between retirement pensions and minimum wage and the real increases witnessed by the minimum wage in this period.Rendimento de aposentadoria e pensão, pobreza rural, distribuição de renda, retirement pensions, rural poverty, income distribution, Food Security and Poverty,

Video monitoring of neovessel occlusion induced by photodynamic therapy with verteporfin (Visudyne®), in the CAM model

The aim of the present study was to monitor photodynamic angioocclusion with verteporfin in capillaries. Details of this process were recorded under a microscope in real-time using a high-sensitivity video camera. A procedure was developed based on intravenous (i.v.) injection of a light-activated drug, Visudyne®, into the chorioallantoic membrane (CAM) of a 12-day-old chicken embryo. The effect of light activation was probed after 24h by i.v. injection of a fluorescent dye (FITC dextran), and analysis of its fluorescence distribution. The angioocclusive effect was graded based on the size of the occluded vessels, and these results were compared with clinical observations. The time-resolved thrombus formation taking place in a fraction of the field of view was video recorded using a Peltier-cooled CCD camera. This vessel occlusion in the CAM model was reproducible and, in many ways, similar to that observed in the clinical use of verteporfin. The real-time video recording permitted the monitoring of platelet aggregation and revealed size-selective vascular closure as well as some degree of vasoconstriction. Platelets accumulated at intravascular junctions within seconds after verteporfin light activation, and capillaries were found to be closed 15min later at the applied conditions. Larger-diameter vessels remained patent. Repetition of these data with a much more sensitive camera revealed occlusion of the treated area after 5min with doses of verteporfin and light similar to those used clinically. Consequently, newly developed light-activated drugs can now be studied under clinically relevant condition